论文部分内容阅读
提供了一种可仅在单面检测结构损伤并能够检测倾斜缺陷的方法,采用叠前偏移算法对在混凝土结构表面各检测点多次激励并采集的反射应力波进行处理,显示结构内部缺陷影像。通过在不同的测试参数下预制损伤混凝土结构的成像试验,分析了叠前偏移剖面分辨率和测试误差的影响因素,并将试验结果与他人采用水平叠加法所得研究结果进行了对比。研究表明,与水平叠加法相比,叠前偏移方法在混凝土缺陷检测中具有较高的精度和较强的对倾斜界面的适应性。当叠前偏移速度偏高时缺陷的检测结果会偏深,反之则偏浅。当满足以下三个条件时,叠前偏移剖面的分辨率较高:1)数值滤波器与有效反射波的主频一致;2)传感器的间距不小于四分之一反射波主波长;3)偏移速度不低于实际传播速度。
The invention provides a method capable of detecting structural damage on one side and capable of detecting inclined defects. A prestack migration algorithm is adopted to process the reflected stress wave that is repeatedly excited and collected at each detection point on the surface of the concrete structure to display the structural internal defects image. Through the imaging test of prefabricated damaged concrete structures under different test parameters, the influencing factors of the resolution and test error of prestack migration section are analyzed. The results of the experiment are compared with the results obtained by others using horizontal stacking method. The research shows that, compared with the horizontal stacking method, the prestack migration method has higher accuracy and adaptability to the inclined interface in the detection of concrete defects. When the pre-stack migration speed is high, the detection result of the defect will be darker, and vice versa. The resolution of the prestack migration profile is high when the following three conditions are met: 1) the numerical filter coincides with the dominant frequency of the effective reflected wave; 2) the spacing between the sensors is not less than one-quarter the dominant wavelength of the reflected wave; 3 The offset speed is not lower than the actual transmission speed.